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62 Cards in this Set
- Front
- Back
Dalton
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hypothesized that for every chemical element there is a corresponding species of objects called atoms; element is a substance that cannot be broken down into other substances.
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Molecule
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Any cluster of atoms that can be isolated.
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Electrolysis
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"splitting be electricity" was developed in the early 19th century. and this allowed rapid discovery of many elements.
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Earths composition
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99% made of 6 elements- Oxygen(o), Silicon(Si), Magnesium(Mg), Iron(Fe), Aluminum(Al), and calcium(Ca)
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Living Organisms Composition
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90% made of 6 elements- hydrogen(H), carbon(C), nitrogen(N), oxygen(O), phosphorous(P), Sulfur(S)
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Stars Composition
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Hydrogen(H) and Helium (He)
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Thompson
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identified a subatomic particle called the electron
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Rutherford
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experimented with gold foil that was penetrated by subatomic particle radiation: scattering and reflection of radiation proved the existence of a dense center of gold atoms: the nucleus
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Nucleus has two types of particles
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proton and neutron
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Life expectancy for Rutherford atom
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1 second
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Bohr
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said electrons exist in various levels or shells located about the nucleus; each shell corresponds to an energy level of the electron
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Ground state of atoms
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all electrons in lower energy levels
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Excited state of atoms
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some or all electrons are in the highest energy levels
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Photon
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a packet of energy with a paradox; both a particle and a wave
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Quantum leap
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electron must dissapear at one level and reappear at another level without transversing the distance.
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spectrum
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total collection of photons emitted by a given atom, therefore each has a unique spectrum.
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spectroscopy
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study of elemental composition using absorption lines.
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Atomic number
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defines the sequence of elements in the table; number of protons in nucleus.
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Alkali earths
Alkalie metals Noble gasses |
first column
second column eigth column |
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Valence electron
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Electrons in outer shell
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chemical bonding
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commonly involves exchange or sharing the valence electron.
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Valence
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number of electrons in the outer shell
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inert gasses
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most stable arrangement of lowest energy because all shells are filled completely with electrons
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Quest of the atom
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to acheieve the lowest energy state it can. so when atoms come near each other they may exchange or share electrons to acheieve this state.
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chemical bonds
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result of redistribution of electrons that leads to a more stable configuration btwn. two or more atoms
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Ionic bonds
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atoms with one less or one more than the noble gas number of atoms.chemical bond in which the electrical for between two oppositely charged ions hold the atoms together.
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Alloy
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combined metals
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Carbon Bond
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the basic bond of all essential molecules of life on earth.
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Organic chemistry
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study of C bonding and related bonding
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Polar molecules
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molecules with either a positive or a negative side.
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hydrogen bonds
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weak electrical attraction developed by the H atoms itself after it is bonded to another element.
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Plasmas
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seas of electrically charged particles at very high temps.
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Crystals
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groups of atoms that occur in a regularly repeating sequence forming a structure in which atoms or molecules occur in a regular and predicatable way.
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crystalline solids
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composed of interlocking crystals
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Polymers
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long and large molecules that are formed from numerous smaller molecules.
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Plastics
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made of intertwined polymers derived from petroleum
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Liquid crystals
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an odd intermediate state of matter that is half way between liquid and crystalline solid.
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sublimation
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change from solid to gas
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Chemical reactions
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atoms and molecules coming together to form larger structure or larger structures breaking apart. the rearrangement of atoms or molecules in chemical compounds.
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Reduction
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chemical reaction in which electrons are transferred to an atom from other elements.
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Acid
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any material when put in water produces positively charged H ions in the solution
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Base
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any material when put in water produces negatively charged OH ions
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Acid-base reaction
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when two are brought together, water is formed
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diameter of atom
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100,000 times the of the nucleus
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Nuclear system
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what goes on in the electron shells is essentially independent.
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Energy of nuclear system
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energy of the nucleus is far greater than the energy of the electrons.
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Mass number
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total number of protons number of nucleus in nucleus
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isotopes
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atoms withe different number of nuetrons but same number of protons
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radiation
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emitted particles of radioactive decay
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stable isotope
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an isotope that is not radioactive
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Becquerel
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discovered and studied radioactivity by using photographic plates that were exposed by unseen radiation
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Alpha decay
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emission of a massive sub-atomic particle consisting of 2 protons and 2 nuetrons
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Beta decay
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emission of an electron and simultaneous creation of a massless neutrino particle.
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Gamma radiation
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emission of an energetic photon, electromagnetic radiaiton this is produced by reshuffling of particles in the nucleus.
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Ionization
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stripping away of electrons by violent interaction and alpha and beta particles.
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Half-life
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average time that it takes for half of a gtroup of radioactive isotopes to undergo radioactive decay
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keck-type telescope
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uses multiple mirrors over a large area in order to achieve the effect of a very large mirror size
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luminosity
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total energy emitted by a star
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Leavitts theory of cephid variables
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absolute brightness is related to time length of bright dim cycle. therefore if we know relative brightness we can figure distance
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Hertzsprung- russell diagram
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graphical way of finding order among stars
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star formation
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nubular spin and collapse due to gravity causes. central mass becomes a star and the disk of gas and dust becomes the collection of planets at critical size
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Neutron star
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all that remains at the core of a supernova explosion
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